Method of drying cores and molds



June 13, 1944. D. J. CAMPBELL 2,351 482 METHOD OF DRYING CORES AND MOLDS Filed Dec. 31, 1941 2 Sheets-Sheet 1 Znnentor DO /c2 c1. ea ball 611M124 M Ddg lttorneg Inventor attorneg June 13 1944. D. J. CAMPBELL METHOD OF DRYING CORES AND MOLDS 2 Sheets-Sheet 2 Filed Dec. 51, 1941 f u dqfiffffll n fzlegfflffill 96AM W. Daja Patented June 13, 1944 OFFICE METHOD or DRYING corms AND MOLDS Donald J. Campbell, Spring Lake, Mich.

Application December 31, 1941, Serial No. 425,148

3 Claims.

My present invention relates primarily to improvements in drying cores and molds, and particularly to the method of drying foundry employed cores and molds composed principally of granular material, and has for its objects first, the provision of a method for drying said cores and molds more expeditiously; second, the provision of a method for drying said cores and molds considerably cheaper; third, the provision of a method for drying said cores and molds uniformly; fourth, the provision of a method for drying said cores and molds thoroughly; fifth, the provision of a method for drying said cores and molds without burning; sixth, the provision of a method whereby other porous granular members can be dried quickly, uniformly, and cheaply.

I attain these named objects and such other objects as may appear from a perusal of the following description, preferably by the employment of the apparatus illustrated by the accompanying drawings, in which Figure 1 is a side elevation View of the apparatus preferably employed in drying cores or molds, including the core drier.

Figure 2 is a vertical sectional view of the air heater and in which is illustrated the air training baffles and air heating tubes.

Figure 3 is a vertica1 sectional view of the core or mold drier in which is shown two cores in iongitudinal cross section and the air pump for reducing the pressure within the cores.

Figure 4 is a top plan view of the core and mold drier base, the view illustrating the arrangement of holes through which the air from the air heater passes into the heating chamber of the heater and also two sockets in which the core arbors are set for supporting the core vertically in the drier.

Throughout the views of the accompanying drawings, similar numerals refer to similar parts or portions of the apparatus preferably employed in practicing my method of drying cores, and referring to the drawings:

Numeral is a carriage supported by wheels 2 and having mounted thereon, at its rear, electrical driven motor 3, adjacent the electric motor, an air compressing blower 4 driven by said motor through V belts 5, adjacent the air compressor blower 4 is air filter 6 connected to the blower by air suction pipe I, and at the front of the carriage is mounted air heater 8 connected at its top to blower 4 by conductor pipe 9 by which air is conducted from the blower to the air heater which preferably comprises an outer casing ||I,'an inner casing II with suitable insulation I: packed between the casings. The in.- ner casing II has heat training baflles l3 extending alternately from the front and from the back or from side to side whereby the air delivered from the blower 4 by air conductor pipe 9 is trained back and forth within the said casings from front to back or side to side in a downward course. Numeral |4 refers to the base of the air heater that serves as a distributor for the heated air conducted from the burner |5 by conductor flue I3 associated with opening H extending through two opposite side walls of the base refractory lining I4. Extending over the lining of the base H is plate I9 provided with a plurality of holes having extending therethrough and welded to the plate, vertically disposed air heating tubes l9 extending upward through the baffles l3 and top plates 20 and 2| having between them, asbestos fibrous zpacking 22, the said plates 20 and 2|, and packing having a plurality of holes through which the air heating tubes 59 extend and are free to expand longitudinally. Numeral 30 refers to the core or mold drier provided with hollow base 3| having in the top of its surrounding wall, packing groove 32 with fibrous packing 33 therein, the said surrounding wall having hot air inlet opening 34 with flange 35 at its outer end, and to which is secured flange 35 of the hot air conductor 33 having flange 36 attached to flange 31 of hollow bushing 38 extending into the lower end of the air heater adjacent the base I4. Within the base 3| and secured thereto is manifold member 33 having a flange 40 resting on the side wall of the base 3| with holes 4| extending through the said flange through which heated air passes from the base to the interior of casing 42 having an outer casing 43 surrounding it with insulation 44 between the-gsaid casings which enclose the cores 45 and 46 built on hollow perforated core arbor 41 havingscrew threaded in their upper end, eye bolts 43 for mechanically handling the cores from the time they are made until they are mounted in the mold, the arbor 41 before the core is built on it is wrapped with rope 49 and has at its lower end enlarged tapered base 50 extending into sockets 5| of the manifold member 39, the said sockets communicating with the cavity 52 of the manifold 39 which has hollow neck 53 having tapered end 54 extending into tapered portion 55 of the gas exit hole 56 extending through the wall of the base 3| and pump engaging flange 51, within the taper portion 55 of the hole 56 is composition packing 58 whereby leakage of heated air is prevented from 2 emmmmmmumawmor thenecklI. Attachedtothepumpengaging flange l1 and-downwardly extending flange ll. b'ycapbolt ",isah-pumphousingll havingcylindrical bore 02 from which extends ports It and 84 opening to hole ll of the hollow base ll. Within the bore 82 of the air pump is suction piston ll having follower member It for packing the leather or other suitable iibre packing 01 against the end of the piston and permitting air to pass to crescent cross-sectional shaped ports 4| opening at their upper ends into the recess between the upwardly extending side members CI of the piston for supporting the yoke 10, in

which slides crank pin block ll, forming a bearing for the crank pin l2 secured to the crank disc II on the shaft 14 of the electric drive motor 18. At the top of the core drier casing 48 is lug I! having a hole extending through it to provide means for attaching a hoist for raising the casings 48 and 44 from the base II, the base having at opposite sides lugs 'I'I whereby the base can be lifted by mechanical means, and

the casing 43 secured to the base for resisting,

the pressure of the air created within the casing 42 by the pressure blower 4.

In practicing my method of drying foundry employed cores, I first provide the apparatus substantially as shown in the several views of the drawings including a core box in which to build the cores 45-48 around the hollow perforated arbor 41 having screwed into its end the eye bolt 48 whereby the arbor in conjunction with the enlarged tapered end ill is held concentric in the core box while the granular sand core material is formed around the arbor which has rope 49 wrapped around it to provide for passage of gas and air to reach the perforations in the sides of the arbor. Having provided the core :box and core arbor as described, I produce the core with the enlarged tapered portion III at one end and the eye bolt 48 at the other, and having Provided the base 31 with the manifold 39 therein, I raise the cores separately by a hoist mechanism hooked through the eye of the eye bolt 48, to a vertical position, I then move the hoist mechanism directly over one of the tapered sockets II in the manifold 39 and then lower the core until the enlarged tapered end of the core arbor rests in the taper socket IQ of the base manifold and detach the hoist mechanism from the eye bolt. When a number of the cores, which is usually four, is mounted as Just described, the casing is lowered over. the cores until it lower edge rests on the packing 33 in the groove in the top of the base wall 32, the casing is then either clamped to the base or weighted suillciently to resist lifting by the air pressure caused by the pressure blower 4. within the casing, the motor Ilsthen startedandbythevbeltsl drivesthe blower ,4 which in turn draws air through the air filter I and blows air through the air-heater l where it is heated to the desired temperature which for certain cores reaches 400 degrees Fahrenheit, the heated air continuing to flow by reason of the blower, passes through air conductor pipe at to the core drier wherein had been mounted the cores for drying as previously described, and wherein the cores are dried quickly,

the time required being less than thirty per cent of the time required to dry similar cores by the usual core oven method. After the cores have been dried, they are given a coat of core wash, this core wash can be applied to the cores before they are placed within the core drier, or applied when the cores are partly or only skin dried. When the cores are thoroughly dried and given the coat of core wash, and the mold in which to cast the Projectile has been provided, each core is raised by a suitable hoist by the eye bolt screwed into the end of the core arbor and lowered into the mold which has a bottom provided with similar tapered sockets to the sockets ll of the manifold 38 in the drier base II, when the cores are placed in the mold, they are anchored therein preferably by a stud screwed into the core arbor in place of the eye bolt 48 which is removed as soon as the cores are set in the mold and the hole extending into the arbor plugged by suitable means which may be the means of the anchor stud or silica sand having a binder mixed in it.

Having described my present method of drying cores and mold portions, I claim:

1. The method of drying foundry employed cores consisting in supporting said cores vertically on a hollow perforated arbor in an enclosing casing, subjecting the exterior of the cores to heated air having a pressure above the pressure of the atmosphere and the interior of the core to a pressure below the pressure of the atmospheric pressure.

2. The method of drying granular cores having a hollow perforated core arbor consisting in subjecting the cough the undried state to heated air under pressure and the hollow perforated core arbor to a lesser pressure whereby heated air is caused to pass from the exterior of the core to the hollow perforated arbor and to the atmosphere.

3. The method of drying granular cores supported by a perforated hollow core arbor consisting in subjecting the core in the undried state to 

